Ubuntu Server postinstall

This manual is suitable for Ubuntu 18.04 and 16.04 server installation.

• rename network interface
  Ubuntu 16.04 | Ubuntu 18.04
• check DNS settings
• sudo without password
• disable AppArmor
• ssh permit root login & create password for root
• configure ssh without password
• install alpine, postfix & mailutils, forward mails for root
• install ntpd
• install logwatch
• install vim
  apt install vim
• install munin client
• add server to smokeping
• install Webmin
• install gcc
• install smartmontools
• install unattended updates